Monitoring system for straw manufacturing apparatus

Abstract

Apparatus and methods for manufacturing compostable, biodegradable drink straws from polyhydroxyalkanoate (PHA) material are disclosed herein. Such apparatus may include a hopper that contains raw PHA material, an extruder that receives the raw PHA material from the hopper and produces extruded PHA material, one or more waters baths that cool the extruded PHA material, a puller that pulls a tubular stream of PHA material through the system, and a cutter that is configured to cut the stream of PHA material into finished straws. A vision system may be provided to monitor a diameter and material thickness of the cooled PHA material. The finished straws may be soil- and marine-biodegradable, as well as home- and industrial-compostable.

What is claimed is: 
     
         1 . Apparatus for manufacturing drink straws from polyhydroxyalkanoate (PHA) material, the apparatus comprising:
 a hopper that contains raw PHA material;   an extruder that receives the raw PHA material from the hopper and produces extruded PHA material, wherein molten PHA material is provided from the extruder through an extruder die, and wherein the extruder die is configured to produce a stream of extruded PHA material that has a tubular shape;   a puller configured to pull the extruded PHA material out of the extruder die and through one or more water baths, wherein the puller includes one or more puller belts composed of a material that enables the puller belt to grip and pull a stream of cooled PHA material; and   a vision system configured to monitor a diameter and material thickness of the cooled PHA material.   
     
     
         2 . The apparatus of  claim 1 , wherein the vision system includes a light projector configured to project light onto the cooled PHA material as the cooled PHA material is being pulled into the puller, and a camera configured to receive light that has passed through or around the cooled PHA material as the cooled PHA material is being pulled into the puller. 
     
     
         3 . The apparatus of  claim 2 , wherein the camera is electrically coupled to an analyzer, the analyzer being configured to determine from a spatial pattern of the received light whether the diameter of the cooled PHA material is within acceptable tolerances. 
     
     
         4 . The apparatus of  claim 3 , wherein the spatial pattern of the received light is affected by the cooled PHA material blocking some of the emitted light that is incident on it. 
     
     
         5 . The apparatus of  claim 4 , wherein, if the analyzer determines that the diameter of the cooled PHA material is outside of acceptable tolerances, the analyzer provides an alarm. 
     
     
         6 . The apparatus of  claim 2 , wherein the camera is electrically coupled to an analyzer, the analyzer being configured to determine from an intensity of the received light whether the material thickness of the cooled PHA material is within acceptable tolerances. 
     
     
         7 . The apparatus of  claim 6 , wherein the intensity of the received light is affected by the cooled PHA material blocking some of the emitted light that is incident on the cooled PHA material. 
     
     
         8 . The apparatus of  claim 7 , wherein, if the analyzer determines that the material thickness is outside of acceptable tolerances, the analyzer provides an alarm. 
     
     
         9 . A vision system for use in manufacturing drink straws from polyhydroxyalkanoate (PHA) material, the vision system comprising:
 a light projector configured to project light onto a stream of PHA material as the PHA material is being pulled from a water bath, the PHA material having a tubular shape;   a camera configured to receive light that has passed through or around the PHA material as the PHA material is being pulled from the water bath; and   an analyzer that is electrically coupled to the camera, wherein the analyzer is configured to determine from the received light whether a diameter and material thickness of the PHA material are within acceptable tolerances.   
     
     
         10 . The vision system of  claim 9 , wherein the analyzer is configured to determine from a spatial pattern of the received light whether the diameter of the PHA material is within acceptable tolerances. 
     
     
         11 . The vision system of  claim 10 , wherein the spatial pattern of the received light is affected by the PHA material blocking some of the emitted light that is incident on the PHA material. 
     
     
         12 . The vision system of  claim 9 , wherein the analyzer is configured to determine from an intensity of the received light whether the material thickness of the PHA material is within acceptable tolerances. 
     
     
         13 . The vision system of  claim 12 , wherein the intensity of the received light is affected by the PHA material blocking some of the emitted light that is incident on the PHA material. 
     
     
         14 . The vision system of  claim 9 , wherein, if the analyzer determines that either the diameter or the material thickness of the PHA material is outside of acceptable tolerances, the analyzer provides an alarm. 
     
     
         15 . The vision system of  claim 9 , wherein the analyzer is a computer processor. 
     
     
         16 . A process for manufacturing drink straws from polyhydroxyalkanoate (PHA) material, the process comprising:
 pulling a stream of extruded PHA material from an extruder die through a water bath to produce a stream of cooled PHA material that has a tubular shape; and   monitoring a diameter and material thickness of the cooled PHA material using a vision system comprising a light projector configured to project light onto the cooled PHA material as the cooled PHA material is being pulled from the water bath, and a camera configured to receive light that has passed through or around the cooled PHA material as the cooled PHA material is being pulled from the water bath,   wherein the camera is electrically coupled to an analyzer, the analyzer being configured to determine from the received light whether the diameter and material thickness of the cooled PHA material are within acceptable tolerances, and   wherein, if the analyzer determines that either the diameter or the material thickness of the cooled PHA material is outside of acceptable tolerances, the analyzer provides an alarm.   
     
     
         17 . The process of  claim 16 , wherein the analyzer is configured to determine from a spatial pattern of the received light whether the diameter of the cooled PHA material is within acceptable tolerances. 
     
     
         18 . The process of  claim 17 , wherein the spatial pattern of the received light is affected by the cooled PHA material blocking some of the emitted light that is incident on the cooled PHA material. 
     
     
         19 . The process of  claim 16 , wherein the analyzer is configured to determine from an intensity of the received light whether the material thickness of the cooled PHA material is within acceptable tolerances. 
     
     
         20 . The process of  claim 19 , wherein the intensity of the received light is affected by the cooled PHA material blocking some of the emitted light that is incident on the cooled PHA material.